As a conventional method for producing tertiary butyl alcohol, a hydration reaction of isobutylene (2-methylpropene) and water using a catalyst has been known.
In Patent Document 1, tertiary butyl alcohol is described as an assistant for carrying out a hydration reaction by making a hydrocarbon and water into a homogeneous liquid phase.
Further, a method is described in Patent Document 2, in which all of the region of hydration reaction is made into a homogeneous liquid phase and further, a step of separating tertiary butyl alcohol is included in the middle of the process.
In Patent Documents 3, 4, 5 and 6, methods for carrying out reactions in heterogeneous liquid phases are described.    Patent Document 1: Japanese Patent Application Laid-Open No. Sho 56-10,124    Patent Document 2: Japanese Patent Application Laid-Open No. Sho 60-233,024    Patent Document 3: International Publication No. WO 99/33,775    Patent Document 4: Japanese Patent Application Laid-Open No. Sho 54-27,507    Patent Document 5: Japanese Patent Application Laid-Open No. Sho 54-30,104    Patent Document 6: Japanese Patent Application Laid-Open No. Sho 54-30,105